Field of the Invention
This invention relates to a method and apparatus for recording compressed audio data on recording medium and a method for transferring compressed audio data. More particularly, it relates to a method and apparatus for recording audio data on recording medium and a method for transferring audio data, in which the recorded data can be random-accessed using the TOC information.
There has so far been known a magneto-optical disc, termed a mini-disc (trademark) which is a recordable and reproducible disc-shaped recording medium of approximately 64 mm in diameter housed within a cartridge. This magneto-optical disc can record stereo audio signals continuing for about 74 minutes in accordance with the Adaptive Transform Acoustic Coding (ATRAC) system. This magneto-optical disc can duplicate audio data because it can record the information in distinction from the conventional digital audio disc known as a compact disc (trademark).
Similarly to the conventional digital audio disc, the magneto-optical disc permits random accessing to the audio data recorded thereon, because an area for table-of-contents information (TOC information) for supervising the recorded audio data is provided in this magneto-optical disc in addition to an area for recording audio data. Therefore, if audio data is overwritten on the magneto-optical disc carrying recorded audio data, it is possible to erase or edit musical numbers without rewriting actual audio data.
There may be envisaged an audio dubbing system in which, for recording audio data compressed to approximately 1/5 on a magneto-optical disc, compressed audio data are directly stored in a server and read out therefrom so as to be recorded without processing the compressed data with decoding or encoding. In case of the audio dubbing system, compressed data can be recorded indifferently on a so-called virgin disc, that is an initialize disc. This, however, is not the case if compressed audio data is to be recorded on a magneto-optical disc on which plural musical numbers of compressed audio data are previously recorded, because the magneto-optical disc is owned by the user and the previously recorded data cannot be erased by overwriting. Therefore, if new compressed audio data is to be recorded on a magneto-optical disc carrying several previously recorded musical numbers, it is necessary to record audio data in vacant recordable areas of the magneto-optical disc, without erasing the previously recorded audio data, while it is also necessary to write the above-mentioned TOC information.
Since the TOC information is the information proper to the disc, it may be contemplated with the above-described audio dubbing system to transfer the TOC information from a recording device to a server as the source for dubbing, and to edit the TOC information in the server which then transfers the processed information back to the recording device. In this case, it is necessary for the server and the recording device to frequently exchange data other than the audio data, thus obstructing efficient recording of audio data.